1. Field of the Invention
The present disclosure relates generally to a suction brush for a vacuum cleaner. More particularly, the present disclosure relates to a suction brush for a vacuum cleaner that is capable of automatically adjusting a distance between a lower casing having a suction inlet formed thereon and a surface to be cleaned depending on whether the surface to be cleaned is a hard floor or a carpet.
2. Description of the Related Art
Generally, a vacuum cleaner is an electric device that draws in dust and other foreign materials existing on a surface to be cleaned using a suction force generated by a vacuum source. Diverse kinds of vacuum cleaners have been developed and used. A canister type vacuum cleaner, which is one of such vacuum cleaners, is typically composed of a main body, a connection part, and a suction brush.
In the main body, a vacuum source, such as a suction motor that generates a suction force, and a dust collection part for collecting the drawn-in dust and foreign materials are installed. The connection part is provided with a handle for user's handling, an extension tube for connecting the handle with a suction brush, and a flexible hose for connecting the handle with the main body. The suction brush is a part that is in contact with the surface to be cleaned and draws in the dust and foreign materials, and has a suction port formed on a bottom surface of the suction brush to draw in the dust and foreign materials.
Representative surfaces to be cleaned by the vacuum cleaner may be a hard floor and a carpet. Here, the hard floor is a general name of smooth surfaces to be cleaned, which are made of stone, lumber, or laminated paper.
In the case where the surface to be cleaned is a hard floor, the suction brush for a vacuum cleaner is apt to stick to the surface to be cleaned, and the manipulation resistance of the suction brush becomes great, so that it is laborious for a user to manipulate the suction brush. By contrast, in the case where the surface to be cleaned is a carpet, the suction brush rarely sticks to the surface to be cleaned. However, in order to draw in dust and other foreign materials existing between wool or fibers closely formed on an upper surface of the carpet, a relatively greater suction force is required in comparison to the hard floor.
The manipulation resistance and the suction force of the suction brush having a suction port formed thereon against the surface to be cleaned are closely connected with the distance between the bottom surface of the suction brush and the surface to be cleaned. That is, as the distance between the bottom surface of the suction brush and the surface to be cleaned is smaller, the manipulation resistance and the suction force become larger, while as the distance between the bottom surface of the suction brush and the surface to be cleaned is larger, the manipulation resistance and the suction force become smaller.
However, on the assumption that the distance between the bottom surface of the suction brush and the surface to be cleaned is kept constant, the hard floor has a large manipulation resistance to cause the user to be laborious, while in the case of the carpet, the suction force becomes weak, and thus the dust and other foreign materials existing between wool of the carpet cannot be effectively drawn-in.
In order to solve this problem, a conventional suction brush for a vacuum cleaner has been developed, which can properly vary the distance between a bottom surface of the suction brush and a surface to be cleaned depending on the type of surface to be cleaned. On an upper surface of such a suction brush, a lever manually operated by a user is formed to be exposed. Accordingly, in the case where the surface to be cleaned is a hard floor, the user can reduce a manipulation resistance of the suction brush by relatively widening the distance between the bottom surface of the suction brush and the surface to be cleaned through the manipulation of the lever. Also, in the case where the surface to be cleaned is a carpet, the user can increase the suction rate of the suction brush by relatively narrowing the distance between the bottom surface of the suction brush and the surface to be cleaned.
However, the user's varying of the distance between the bottom surface of the suction brush and the surface to be cleaned through the user's manual operation of the lever should be done whenever the surface to be cleaned is changed, and this causes the user inconvenience.